Origin of Life “…sparked by just the right combination of physical events & chemical...
-
Upload
christian-holland -
Category
Documents
-
view
223 -
download
1
Transcript of Origin of Life “…sparked by just the right combination of physical events & chemical...
![Page 1: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/1.jpg)
Origin of Life
“…sparked by just the right combination of physical events & chemical processes…”
“…sparked by just the right combination of physical events & chemical processes…”
![Page 2: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/2.jpg)
Bacteria Archae-bacteria
AnimaliaFungiProtista Plantae
4500
4000
3500
3000
2500
2000
500
1500
0
1000
Formation of earth
Molten-hot surface ofearth becomes cooler
Oldest definite fossilsof prokaryotes
Appearance of oxygenin atmosphere
Oldest definite fossilsof eukaryotes
First multicellularorganisms
Appearance of animalsand land plants
Colonization of landby animalsPaleozoic
Mesozoic
Cenozoic
Mill
ion
s o
f y
ears
ag
o
AR
CH
EA
N PR
EC
AM
BR
IAN
PR
OT
ER
OZ
OIC
The evolutionary tree of life can be documented with evidence.The Origin of Life on Earth is another story…
The evolutionary tree of life can be documented with evidence.The Origin of Life on Earth is another story…
![Page 3: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/3.jpg)
The Origin of Life is a Hypothesis• Special Creation
– Was life created by a supernatural or divine force?
– not testable• Extra-terrestrial Origin
– Was the original source of organic (carbon) materials comets & meteorites striking early Earth?
– testable• Spontaneous Abiotic Origin
– Did life evolve spontaneously from inorganic molecules?
– testable
![Page 4: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/4.jpg)
Conditions on early Earth
• Reducing atmosphere– water vapor (H2O), CO2, N2, NOx, H2, NH3, CH4, H2S
– lots of available H & its electron– no free oxygen
• Energy source– lightning, UV radiation,
volcanic
low O2 = organic molecules do not breakdown as quickly
low O2 = organic molecules do not breakdown as quickly
What’s missingfrom thatatmosphere?
![Page 5: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/5.jpg)
Water vapor
Condensed liquid with complex, organicmolecules
CondenserMixture of gases("primitiveatmosphere")
Heated water("ocean")
Electrodes discharge sparks(lightning simulation)
Water
Origin of Organic Molecules
• Abiotic synthesis– 1920
Oparin & Haldane propose reducing atmosphere hypothesis
– 1953Miller & Urey test hypothesis
• formed organic compounds– amino acids– Adenine
• Show Miller Urey Animation
CH4
NH3
H2
![Page 6: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/6.jpg)
Stanley MillerUniversity of Chicago
produced-amino acids
-hydrocarbons-nitrogen bases-other organics
Why was this experimentimportant??!
![Page 7: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/7.jpg)
Organic monomers/polymer synthesis
• These molecules served as monomers of building blocks for the formation of more complex molecules, including amino acids & nucleotides.
• Joining of the monomers produced polymers with the ability to replicate, store & transfer information.
• The RNA World hypothesis proposes that RNA could have been the earliest genetic material.
RNA~ DNA template?
![Page 9: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/9.jpg)
Key Events in Origin of Life• Origin of Cells (Protobionts)
– lipid bubbles separate inside from outside metabolism & reproduction
• Origin of Genetics (1st Genetic Material!)– RNA is likely first genetic material– multiple functions: encodes information (self-replicating),
enzyme, regulatory molecule, transport molecule (tRNA, mRNA)
• makes inheritance possible• makes natural selection & evolution possible
• Origin of Eukaryotes– endosymbiosis
![Page 10: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/10.jpg)
First Eukaryotes• Development of internal membranes
– create internal micro-environments– advantage: specialization = increase efficiency
• natural selection!
infolding of theplasma membrane
DNA
cell wall
plasmamembrane
Prokaryoticcell
Prokaryotic ancestor of eukaryotic cells
Eukaryoticcell
endoplasmicreticulum (ER)
nuclear envelope
nucleus
plasma membrane
~2 bya
![Page 11: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/11.jpg)
1st Endosymbiosis
Ancestral eukaryotic cell
Eukaryotic cellwith mitochondrion
internal membrane system
aerobic bacterium mitochondrion
Endosymbiosis
• Evolution of eukaryotes– origin of mitochondria– engulfed aerobic bacteria, but
did not digest them– mutually beneficial relationship
• natural selection!
![Page 12: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/12.jpg)
mitochondrion
chloroplast
Eukaryotic cell withchloroplast & mitochondrion
Endosymbiosis
photosyntheticbacterium
2nd Endosymbiosis• Evolution of eukaryotes
– origin of chloroplasts – engulfed photosynthetic bacteria,
but did not digest them– mutually beneficial relationship
• natural selection!
Eukaryoticcell with mitochondrion
![Page 13: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/13.jpg)
• Evidence– structural
• mitochondria & chloroplasts resemble bacterial structure
– genetic• mitochondria & chloroplasts
have their own circular DNA, like bacteria– functional
• mitochondria & chloroplasts move freely within the cell
• mitochondria & chloroplasts reproduce independently from the cell
Theory of Endosymbiosis
Lynn Margulis
![Page 14: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/14.jpg)
Molecular & genetic evidence from existing and extinct organisms indicates all organisms on Earth share a
common ancestral origin of life
Molecular building blocks are common to all life forms
Common genetic code are shared by all modern organisms.
Metabolic pathways are conserved across all currently recognized domains (bacteria, archea, & eukarya)
![Page 15: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/15.jpg)
The Universal Tree of Life
1. Last common ancestor of all living things.
2. Possible fusion of bacterium with archea making eukaryotes
3. Symbiosis of mitochondrial ancestor with ancestor of eukaryotes
4. Symbiosis of chloroplast ancestor with ancestor of green plants
![Page 16: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/16.jpg)
Cambrian explosion• Diversification of Animals
– within 10–20 million years most of the major phyla of animals appear in fossil record
543 mya
![Page 17: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/17.jpg)
![Page 18: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/18.jpg)
FUNCTIONS OF LIFE
![Page 19: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/19.jpg)
In order to perform these functions…what do we need?
CELLS!!!!
![Page 20: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/20.jpg)
Parts of the Cell Theory
• All organisms are composed of one or more cells.
• Cells are the smallest units of life
• Cells can only come from pre-existing cells.
![Page 21: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/21.jpg)
Evidence to support cell theory
• Through the use of microscopes scientists have amassed even more credibility on the part of cells being the smallest unit of life.
• As of this date we have not been able to find an organism that is not made of at least one cell.
• Louis Pasteur performed experiments to support the principle that all cells come from other cells.
![Page 22: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/22.jpg)
Various Microscopes Used Today
Electron Microscope (EM)Scanning Electron Microscope (SEM)
Light Microscope
![Page 23: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/23.jpg)
What’s the Difference between the TEM and SEM?
Transmits a beam of electrons through a thin section of a specimen.
Perceives the excited electrons coming off of the surface or the gilded surface of a specimen.How do EM’s get
Such high magnification& resolution?
![Page 24: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/24.jpg)
![Page 25: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/25.jpg)
How has biology been limited by available technology in the past?
What kinds of things were correctly postulated before the
technology we have today?
How are scientists still limited by available technology?
![Page 26: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/26.jpg)
Fig. 4.3 A scale of visibility
![Page 27: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/27.jpg)
PROKARYOTIC VS EUKARYOTIC CELLS UNDER THE MICROSCOPE
![Page 28: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/28.jpg)
BESIDES SIZE..WHAT ELSE IS DIFFERENT
BETWEEN PROKARYOTE CELLS
AND EUKARYOTE CELLS?
GET TOGETHER WITH A PARTNER
AND COME UP WITH AS MANY
DIFFERENCES AS POSSIBLE. THE WINNERS GET
CANDY!!!
![Page 29: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/29.jpg)
PROKARYOTIC
• Smaller & simpler• Less than 10µm in diameter• DNA in ring form without
protein• DNA is free floating• No mitochondria• 70S ribosomes• No internal
compartmentalization to form organelles
• Thought to be the 1st cells on Earth.
• Reproduce by Binary Fission• EX: BACTERIA
EUKARYOTIC• Bigger & more complex• More than 10µm• DNA with proteins as
chromosomes/chromatin• DNA enclosed in nucleus• Mitochondria is present• 80S ribosomes• Internal compartmentalization
present to form many types of organelles.
• EX: EVERYTHING EXCEPT BACTERIA
![Page 30: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/30.jpg)
PROKARYOTIC CELL
What do you think the functions are?
![Page 31: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/31.jpg)
• Capsule - Found in some bacterial cells, this additional outer covering protects the cell when it is engulfed by other organisms, assists in retaining moisture, and helps the cell adhere to surfaces and nutrients.
• Cell Wall - Outer covering of most cells that protects the bacterial cell and gives it shape.
• Cytosol - A gel-like substance composed mainly of water that also contains enzymes, salts, cell components, and various organic molecules; located in the cytoplasm. It is where organelles are found
• Cell Membrane or Plasma Membrane - Surrounds the cell's cytoplasm and regulates the flow of substances in and out of the cell.
• Pili - Hair-like structures on the surface of the cell that attach to other bacterial cells. Shorter pili called fimbriae help bacteria attach to surfaces.
• Flagella - Long, whip-like protrusion that aids in cellular locomotion.• Ribosomes - Cell structures responsible for protein production.• Plasmids - Gene carrying, circular DNA structures that are not involved in
reproduction.• Nucleiod Region - Area of the cytoplasm that contains the single bacterial
DNA molecule.
![Page 32: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/32.jpg)
What do membrane-bound organelles do for the cell?
• They give the cell compartments in which to perform certain functions, under specific conditions, with all the materials needed in one location.
How do you think prokaryotic cells perform cellular functions without
compartmentalized cells?
• They have folds in their plasma membranes that act as compartments.
![Page 33: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/33.jpg)
CELL PARTS & FUNCTIONS
![Page 34: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/34.jpg)
NUCLEUSWHAT PARTS ARE IN THE NUCLEUS?
DNA, mRNA, histone proteins surrounding DNA, free floating nucleotides, ribosomal subunits around the nucleolus
WHAT’S THE FUNCTION?
To protect the DNA
![Page 35: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/35.jpg)
WHAT CAN YOU EXPECT FROM CELLS THAT DON’T HAVE A NUCLEUS
AROUND THEIR DNA, SUCH AS PROKARYOTES?
BECAUSE THE DNA IS EXPOSED, PROKARYOTES HAVE A MUCH HIGHER RATE
OF DNA MUTATION.
![Page 36: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/36.jpg)
RED BLOOD CELLS DO NOT HAVE A NUCLEUS AT MATURITY. HOW DO
THEY FUNCTION WITHOUT IT?
AT MATURITY THEY HAVE ALL THE PROTEINS & ENZYMES NEEDED FOR THE REMAINDER OF THEIR SHORT LIFE SPAN
HOW DO RED BLOOD CELLS REPRODUCE?
THEY DON’T. NEW RBC’S ARE MADE IN BONE MARROW
![Page 37: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/37.jpg)
If mature red blood cells have no nucleus or DNA why do forensics need
blood for DNA analysis?
![Page 38: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/38.jpg)
NUCLEOULUS
THE NUCLEOLUS IS ALSO DNA BUT HAS A SEPARATE NAME, EVEN THOUGH IT IS
NOT A SEPARATE COMPARTMENT.
WHY DO YOU THINK THIS REGION HAS ITS OWN NAME?
IT APPEARS AS A DENSE REGION ON A LIGHT MICROSCOPE & WAS ORIGINALLY THOUGHT TO BE A DIFFERENT COMPARTMENT, BUT WITH IMPROVED TECHNOLOGY IT WAS RECOGNIZED AS A HIGHLY STRUCTURED REGION OF DNA WITH CONSTANT ACTIVITY; THE DENSITY IS DUE TO THE PRESENCE OF GRANULES & FIBERS HOLDING THE RIBOSOMAL DNA IN PLACE.
![Page 39: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/39.jpg)
RIBOSOMES
![Page 40: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/40.jpg)
ENDOPLASMIC RETICULUM
SMOOTH
Synthesizes lipids; detoxifies drugs and poisons.
ROUGH
Helps synthesize proteins to be exported from the cell.
![Page 41: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/41.jpg)
GOLGI APPARATUS (AKA GOLGI COMPLEX)
Center of manufacturing, warehousing, sorting, and shipping
![Page 42: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/42.jpg)
LYSOSOMES
![Page 43: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/43.jpg)
VACUOLES
![Page 44: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/44.jpg)
![Page 45: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/45.jpg)
MITOCHONDRIA
![Page 46: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/46.jpg)
CHLOROPLASTS
![Page 47: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/47.jpg)
HOW ARE THE MITOCHONDRIA AND CHLOROPLASTS SIMILAR TO
PROKARYOTIC CELLS?
SIZE BOTH HAVE THEIR OWN DNA
THEY ARE NOT PART OF THE ENDOMEMBRANE
SYSTEM
SOME PROTEINS NEEDED ARE MADE BY THEIR RIBOSOMES LOCATED IN THEIR MEMBRANE & OTHER PROTEINS ARE BROUGHT IN FROM THE CYTOSOL
THEY REPRODUCE IN A SEMIAUTONOMOUS
MANNER
![Page 48: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/48.jpg)
Why might we do a mitochondrial DNA test?
• It is most effective in determining siblings– Mitochondrial DNA is past on by mom only so all
siblings will have the same mitochondrial DNA.
• US military uses it for identification of skeletons from old war zones.– Highly preserved compared to nucleus DNA
![Page 49: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/49.jpg)
Why do mitochondria & chloroplasts have so many membranes in them?
For increased surface area used for the energy conversion processes that occur in
these organelles.
![Page 50: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/50.jpg)
PLASTIDS- in plant cells not animal cells• Leucoplasts- energy storage
• Chromoplasts- color centers
• Chloroplasts- essential for photosynthesis
Are colorless and store starch (amylose)
-mostly in roots & tubers
Have pigments that give flowers and fruits their color
Contain green pigment (chloropyll) along with enzymes & various molecules that aid them in photosynthesis
![Page 51: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/51.jpg)
PEROXISOMES
Produces hydrogen peroxide by transferring hydrogen to oxygen.
-use oxygen to breakdown fatty acids
(send to mitochondria for cellular respiration fuel)
-in liver cells they detoxify alcohol & other harmful compounds by transferring hydrogen from the poisons to oxygen.
Once hydrogen peroxide is made, other enzymes within the peroxisome changes it to water.
Seedlings have peroxisomes in order to convert fatty acids
to sugar until it is able to photosynthesize.
![Page 52: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/52.jpg)
CENTRIOLES
![Page 53: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/53.jpg)
CYTOSKELETON
SUPPORT, MOTILITY, AND REGULATION
![Page 54: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/54.jpg)
Fig. 4.19
![Page 55: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/55.jpg)
![Page 56: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/56.jpg)
Microtubules(originate from centrosomes)
• Help determine/maintain cell shape (by resisting compression)
• Involved in cell movement (flagella, cilia)
• Involved in the position of organelles within the cell– function like tracks within the cell, on which cargoes of
materials like vesicles or organelles can be transported
• Involved in the movement of chromosomes during cell division.
![Page 57: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/57.jpg)
![Page 58: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/58.jpg)
Antimitotics• Cancer fighting drugs that inhibit microtubes
from breaking down and reassembly.
![Page 59: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/59.jpg)
Microfilaments
• Maintain cell shape (bearing tension)• Responsible for gross changes of cell shape
– Pseudopodia– Muscle contractions– Cleavage during cell division– Phagocytosis.
![Page 60: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/60.jpg)
MICROFILAMENTS
![Page 61: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/61.jpg)
Intermediate Filaments(keratin filaments)
• Permanent structures in the cell• Helps maintain rigid cell shape• Anchor organelles in fixed positions when
necessary (EX: nucleus)
![Page 62: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/62.jpg)
People with a rare mutation in their keratin genes that prevents proper assembly of keratin filaments have skin cells that rupture from even slight pressure
Epidermolysis bullosa simplex or EBS
![Page 63: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/63.jpg)
How are microtubules different from intermediate filaments?
• Unlike intermediate filaments all microtubules are made up of a single kind of protein called tubulin.
• Microtubules are assembled in such a way that they have a polarity (that is, one end is different from the other).
• Microtubules are rapidly assembled and broken down many times within a short span of time, while intermediate filaments are more stable.
MICROTUBULES INTERMEDIATE FILAMENTS
![Page 64: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/64.jpg)
MOTOR PROTEINS
![Page 65: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/65.jpg)
CELL WALLEXTRACELLULAR STRUCTURE
MUCH THICKER THAN PLASMA MEMBRANES
(ranging from 0.1micrometers to several micrometers)
![Page 66: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/66.jpg)
Outermost regions of various cell types
Cell Outermost part
Bacteria Cell wall of peptidoglycan
Fungi Cell wall of chitin
Yeasts Cell wall of glucan and mannan
Algae Cell wall of cellulose
Plants Cell wall of cellulose
Animals No cell wall, plasma membrane secretes a mixture of sugar & proteins called glycoproteins that forms the extracellular
matrix
![Page 67: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/67.jpg)
Extracellular Matrix (ECM) of Animal Cells
![Page 68: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/68.jpg)
Intercellular Junctions
• How cells adhere to each other, interact with each other, and communicate with each other.
PLANTS:
• PLASMODESMATA
•CYTOSOL PASSES THROUGH BETWEEN CELLS ALLOWING WATER AND SMALL SOLUTES TO PASS FROM CELL TO CELL.
![Page 69: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/69.jpg)
Animals: Cells pressed together bound together by specific proteins.
Prevent leakage of extracellular fluid
Like rivets, they fasten cells together. Intermediate filaments anchor desmosomes in the cytoplasm.
Cytoplasmic channels from one cell to the next.
Like plasmodesmatas in plants
![Page 70: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/70.jpg)
CELL FRACTIONIZATION
![Page 71: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/71.jpg)
Variations among Eukaryotic Cells
Plant cells• Exterior of cell includes cell
wall• Have chloroplasts• Possess large vacuole that’s
centrally located• Store carbohydrates as
starch• Do not contain centrioles• Has a fixed often angular
shape
Animal cells• Exterior of cell includes
plasma membrane• No chloroplasts• Vacuoles are usually not
present or are very small• Store carbohydrates as
glycogen• Have centrioles• Is flexible and more likely to
be rounded in shape.
![Page 72: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/72.jpg)
Cell Reproduction & Differentiation
• Multi-cellular organisms usually start as 1 cell.• Cells reproduce at a rapid rate and go through
differentiation.– This occurs to produce all the required cell types that
are necessary for the organisms well-being.• Genes on a chromosome allow for this process to
occur.– All cells contain all of the genetic information to make
the entire organism.– Each cell becomes a specific type of cell depending
on which DNA segment becomes active.
![Page 73: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/73.jpg)
Stem Cells
• Retain the ability to divide and differentiate.• Plants have these cells in their meristematic
tissue (near root & stem tips).– Gardeners take cuttings from stems or roots to grow a
new plant.• In the 1980’s, pluripotent (embryonic stem cells)
were found in mice.– Problem: stem cells can’t be distinguished on
appearance. They can only be isolated based on behavior.
![Page 74: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/74.jpg)
Research on using stem cells
• To replace differentiated cells lost due to injury and disease.– EX: Parkinson’s Disease & Alzheimer’s disease are
caused by loss of brain cells.– EX: Certain types of diabetes deplete the pancreas
of essential cells.
• Using tissue specific stem cells– Blood stem cells replace damaged bone marrow
![Page 75: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/75.jpg)
NUCLEUS
ROUGH ER
MITOCHONDRIA
LYSOSOME
SMOOTH ER
NUCLEAR ENVELOPE
GOLGI APPARATUS
PLASMA MEMBRANE
![Page 76: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/76.jpg)
CELL WALLPILI NUCLEOID
PLASMA MEMBRANE
RIBOSOMES
![Page 77: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/77.jpg)
![Page 78: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/78.jpg)
Cell membrane
![Page 79: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/79.jpg)
DESCRIBLE THE CELL PARTS THAT WOULD BE FOUND IN GREATER NUMBERS IN:
STOMACH CELLS:
POTATO CELLS:
WHITE BLOOD CELLS:
LIVER STORAGE CELLS:
MESOPHYLL (PLANT LEAF) CELLS:
MUSCLE CELLS:
ADIPOSE CELLS:
LIVER DETOX CELLS:
rough ER for secretion
vacuoles for storage
vacuole for starch storage
lysosomes to breakdown engulfed pathogens
chloroplasts for photosyntheis
mitochondria for ATP peroxisomes & smooth ER to break down toxins
vacuoles for storage
![Page 80: Origin of Life “…sparked by just the right combination of physical events & chemical processes…”](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649e745503460f94b74de6/html5/thumbnails/80.jpg)
How do cells recycle?• Endomembrane system:
– Cycle phospholipids
• Lysosomes, peroxisomes, & rough ER:– Breakdown macromolecule parts & reassemble
them
• Cytoskeleton:– Constant flow of assembling & de-assembling
subunits.
Why are cells so efficient at recycling?For the same reasons developing countries are good at
recycling; limited resources and limited energy